1. Field of the Invention
The present invention relates to a firefighting double-nozzle deluge gun which is controlled in accordance with a water-reaching range so that an optimal watering pattern can be obtained in any water-reaching range.
2. Description of the Related Art
Deluge guns for shooting water or fire extinguishing liquids from nozzles to fire sources are known as one type of firefighting devices which are provided in buildings such as hotels, schools and atriums.
The water-reaching range of a firefighting deluge gun is controlled by adjusting the shooting pressure and/or the elevation angle of the nozzle. If the nozzle is maintained at a certain elevation angle and the shooting pressure is varied, the water-reaching range varies in accordance with the shooting pressures, and the watering pattern (a pattern of area which receives a predetermined amount of water or more per a unit of time) varies with the water-reaching ranges, as indicated in FIG. 8.
However, watering by using a known firefighting deluge gun having one nozzle results in a spindle-shaped watering pattern, as shown in FIG. 8, which becomes narrower toward the front and rear ends thereof. Thus, the known firefighting single-nozzle deluge guns are liable to fail to achieve substantially wide watering patterns. Particularly, during a short-range operation, the watering pattern becomes narrow, in other words, it becomes a bar-shape instead of a spindle-shape, and, thus, the effective watering area becomes inconveniently small.
To enhance the fire extinguishing performance, there has been provided a deluge gun having two nozzles.
Japanese Patent Application Laid-open No. 60-7124 discloses one type of double-nozzle deluge gun in which the two nozzles are parallelly operated about a single rotation axis and a single swing (elevation angle) axis so as to always face in the same direction. Japanese Patent Application Laid-open No. 60-160851 discloses another type of double-nozzle deluge gun comprising a nozzle for short-range watering and a nozzle for long-range watering. In these double-nozzle deluge guns, the water-reaching range is varied by varying the shooting pressure and/or the elevation angle of the nozzle, or selectively using the nozzles with different ranges.
However, watering by using a known firefighting deluge gun having one nozzle results in a spindle-shaped watering pattern, as shown in FIG. 8, which becomes narrower toward the front and rear ends thereof. Thus, the known firefighting single-nozzle deluge guns are liable to fail to achieve substantially wide watering patterns. Particularly, during a short-range operation, the watering pattern becomes narrow, in other words, it becomes a bar-shape instead of a spindle-shape, and, thus, the effective watering area becomes inconveniently small.
While, a double-nozzle deluge gun having nozzles of the same type (with the same water-reaching ranges) has a problem in that the watering areas of the individual nozzles are liable to become separated during a short-range watering operation because the widths of the watering areas are reduced during the operation. Further, a double-nozzle deluge gun having nozzles with different ranges has a problem in that the width of the watering pattern of the long-range nozzle is reduced as the range is decreased, similar to the case of the watering pattern of the single-nozzle deluge gun.